计量基准

Through the international cooperation the metrologists are striving to redefine the mass standard depending on unchanging properties of nature based on the concept of Avogadro constant and Planck's constant.

近年来，计量学家通过国际合作，试图基于自然的不变性质、阿佛加德罗常数和普朗克常数的概念重新定义质量基准。

In principle this standard is a self developed automatic balance bridge,in which its resistance arms can be changed automatically,and is used for the calibration of the RF voltage.

我国于1980年建成射频电压基准[1]，20多年来，它在保证射频电压计量器具的量值准确和统一的工作中做出了宝贵的贡献。

The results of theoretical analysis and experiments indicate that in the frequency band of 10 to 3 000 MHz and voltage range of 0.1 to 2 V,the uncertainty is 0.25% to 0.7% and the confidence level is 99.73%. Metrology ; Voltage standard ; Bolovac ; Thin film bolometric bridge with resistance regulation network circuit ; Double thin film bolometer ; RF mount ; Uncertainty evaluation

在近期的技术改造[2]中，我们研制出电阻臂可变的自动平衡电桥，重新研制了双薄膜测热电阻，建立了射频电压自动校准系统，从而使该基准的计量性能有了很大提高，其主要技术指标如下：测量范围为0·1~2·0V；频率范围为10~3 000MHz；不确定度为0·25%~0·7%(k=3)；工作方式为自动测试。2工作原理和构成2.1工作原理射频电压基准是建立在功率替代原理的基础

National measurement standards may be primary standards, which are primary realizations of the SI units or agreed representations of SI units based on fundamental physical constants, or they may be secondary standards which are standards calibrated by another national metrology institute.

国家测量标准可以是基准，它们是 SI 单位的原级实现或是以基本物理常量为根据的 SI 单位约定的表达式，或是由其他国家计量院所校准的次级标准。

NOTE 3 Calibration laboratories that maintain their own primary standard or representation of SI units based on fundamental physical constants can claim traceability to the SI system only after these standards have been compared, directly or indirectly, with other similar standards of a national metrology institute.

注3： 持有自己的基准或基於基本物理常量的 SI 单位表达式的校准实验室，只有在将这些标准直接或间接地与国家计量院的类似标准进行比对之后，方能宣称溯源到 SI 单位制。

Also it can be used in the nuclear science and engineering research for absolute measurement of nuclear decay rate.

它可供计量实验室建立放射性活度基准设备用，也可用于核科学研究和工程中核衰变率的绝对测量。

For example, since the earth to the base, relative to the sun to measure time to get the sun when the time is measured relative to the stars, known as the sidereal time, to atomic transition frequency as a benchmark time for the system is called atomic time.

例如，以地球自转为基准，相对于太阳来计量时间得到的是太阳时，相对于恒星来计量时间，称为恒星时，以原子的跃迁频率为基准的时间系统称为原子时。

The results presented in this work can be used as a bench mark against which to evaluate the significance of the stress value obtained from empirically based nonmetric multidimensional scaling. In addition, the suggestions for the use of stress values as goodness of fit measures were proposed.

研究结果可做为实际应用压力系数评估非计量多向度量尺法之构形适合度的参照基准，此外，研究者就研究发现提出以压力系数判断和决定资料之构形向度时应注意的事项。

Finally this paper achieves a new method about Modeling and simulation of the liquid cargo tank. 3 The calculation of tank capacity based on UG/CAD modeling is studied in this paper . The calculation datum point is gotten by interposition of ship hull at first. Then many datum plane that go through different sounding and heel is created . The cad modeling of oil is created by the bool of the datum plane and the cad modeling of tank.

在使用UG建立准确的计量舱满舱CAD模型的基础上，采用插值得到计量舱计量基准，根据不同测深和不同纵倾值，建立一系列计量液位面，计量舱满舱CAD模型和计量液位面布尔运算后得到实际油液的CAD模型，通过计算油液CAD模型的体积，实现对计量舱容积的计量。

Benchmarking is an effective way to achieve the ultimate competitive advantage and superior customer satisfaction.

基准计量是获得根本性的竞争优势和令顾客十分满意的有效途径。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。